Advances in genetics have empowered gene therapy as a cancer treatment, however there are many challenges to delivering genes specifically to target disease sites. Presented here is the development of a new non-viral gene delivery vehicle, consisting of branched polyethyleneimine (bPEI) condensed plasmid DNA polyplexes encapsulated within a PR_b functionalized stealth liposome, for the delivery of genes specifically to &alpha<sub>5</sub>&beta<sub>1</sub> integrin overexpressing cancer cells. This new transfection agent mediated higher gene expression than non-targeted stealth liposomes and unencapsulated polyplexes in tissue culture. In a liver-metastatic colorectal cancer mouse model, PR_b functionalized stealth liposomes outperformed non-targeted stealth liposomes and was able to specifically transfect the tumor site while avoiding healthy tissues. In addition, a comparative investigation of the transfection mechanism of PR_b functionalized nanoparticles, DOTAP/DOPE lipoplexes, bPEI polyplexes and stealth liposomes was carried out in DLD-1 cells. Results demonstrated that PR_b functionalized nanoparticles were optimally balanced for the transfection of DLD-1 cells with high colloidal stability, fast integrin mediated internalization kinetics, caveolae mediated uptake and endosomal escape. To further increase the specificity of gene expression in cancer tissue, a new therapeutic plasmid DNA (pNF-&kappaB-DTA) was developed with expression of Diphtheria toxin fragment-A (DTA) gene regulated by the transcriptional activity of NF-&kappaB, which is a transcription factor upregulated in cancer. The multi-targeted gene delivery system formed by encapsulating pNF-&kappaB-DTA/bPEI polyplexes in PR_b functionalized stealth liposomes showed more specific gene expression in cancer cells versus healthy cells compared to either individually targeted system. Transfecting cancer cells using the multi-targeted gene delivery system resulted in a dose-dependent reduction of cellular protein expression and a dose-dependent increase in cytotoxicity. Our therapeutic delivery system specifically eradicated on average 70% of a variety of cancer cells while minimally affecting healthy cells. Moving forward, the modular nature of our non-viral delivery vehicle design can facilitate targeting novel pairs of extracellular receptors and upregulated transcription factors for applications beyond cancer gene therapy.
University of Minnesota Ph.D. dissertation. December 2013. Major: Chemical Engineering. Advisor: Efrosini Kokkoli. 1 computer file (PDF); xv, 123 pages.
Adil, Maroof Mohammad.
A platform for next-generation cancer therapies: multi-targeted nonviral vectors for site-specific gene delivery and expression.
Retrieved from the University of Minnesota Digital Conservancy,
Content distributed via the University of Minnesota's Digital Conservancy may be subject to additional license and use restrictions applied by the depositor.